The 3rd Generation Partnership Project (3GPP) developed the standards used by Long Term Evolution (LTE) cellular communication systems. LTE is a standard for wireless data communications technology that has evolved from the GSM/UMTS standards. The goal of LTE is to increase the capacity and speed of wireless data networks using new Digital Signal Processing (DSP) techniques and modulation schemes that were developed in the past decade. The LTE wireless interface is incompatible with second generation (2G) and third generation (3G) networks, and operates via a separate wireless spectrum.
To provide control information from the base station to the mobile subscriber's user equipment (UE), e.g., a mobile phone, LTE uses downlink physical control channels. The physical control channels comprise a physical broadcast channel (PBCH) and a physical downlink control channel (PDCCH) that both serve a variety of purposes. The PBCH provides network configuration information to the UEs such as transmitted signal bandwidth and System Frame Number (SFN). The PDCCH is primarily used to convey the scheduling decisions to individual UEs, i.e., scheduling assignments for uplink and downlink transmissions.
The control information for PDCCHs is encoded in a control region comprising a number of Orthogonal Frequency Division Multiplex (OFDM) symbols varying from one up to four that are located at the start of each subframe. Both the PBCH and PDCCH use a tail-biting convolutional code to encode information for the UE. Multiple PDCCH messages can be transmitted by the base-station in the control region and these different messages will typically be addressed to different UEs. Moreover, a number of different possible formats for these messages can be used for the eNode-B transmission. As the base-station does not explicitly signal the location of these messages in the control region nor their formats, the UEs need to blindly detect the presence of relevant control information and decode this information according to the identified format. The blind detection and decoding process that needs to be performed by the UE increases the computational complexity and can also lead to an increase in the false detection of control messages. The invention described therein provides techniques which reduce the processing complexity and improve the accuracy of the blind detection and decoding.